They will continue maintaining the International Space Station together, though

According to The New York Times, NASA announced yesterday that it is halting many forms of contact with Russian government representatives due to Russia's "ongoing violation of Ukraine's sovereignty and territorial integrity."

Russian and American relations have become a bit strained after Russia annexed Crimea, a Ukrainian peninsula with past ties to Russia. In response, the U.S. has imposed sanctions.

Despite these issues, the two space agencies have managed to maintain a normal relationship. The retirement of the U.S. space shuttle program in 2011 means that the U.S. doesn't have a way to launch astronauts to the International Space Station (ISS), so it depends on Russian Soyuz capsules to get there instead. Russia also benefits because it receives $70 million for every astronaut it launches.

But it seems even the space agencies have problems now, as NASA has decided to sever many ties with the Russian government -- except when it comes to operating the ISS.

[SOURCE: Mashable]

"Given Russia's ongoing violation of Ukraine's sovereignty and territorial integrity, NASA is suspending the majority of its ongoing engagements with the Russian Federation," said NASA in a statement. "NASA and Roscosmos will, however, continue to work together to maintain safe and continuous operation of the International Space Station. NASA is laser focused on a plan to return human spaceflight launches to American soil, and end our reliance on Russia to get into space.

"This has been a top priority of the Obama Administration’s for the past five years, and had our plan been fully funded, we would have returned American human spaceflight launches – and the jobs they support – back to the United States next year. With the reduced level of funding approved by Congress, we’re now looking at launching from U.S. soil in 2017. The choice here is between fully funding the plan to bring space launches back to America or continuing to send millions of dollars to the Russians. It’s that simple. The Obama Administration chooses to invest in America – and we are hopeful that Congress will do the same."

NASA is reportedly suspending travel to Russia, teleconferences, visits by Russian government officials to NASA facilities and even the exchange of emails with Russian officials.